1. Field of the invention
This invention relates to the baling of hay or the like and, more particularly, to the wrapping of generally cylindrical bales with bindings of twine or the like for the purpose of maintaining the structural integrity of the bales upon discharge thereof from a rotary bale forming machine and thereafter during storage, transportation or handling.
The invention encompasses both an improved method of patterning and applying such bindings to bales and related, improved apparatus, including electrical cycling control means, for practicing the method in a preferred manner.
2. Description of the Prior Art
Generally cylindrical or so-called "round" bales of hay are normally formed with machines commonly referred to as "rotary balers", which typically move through a field receiving hay as it is cut into a chamber where it is rotated as it accumulates until a bale of the desired size has been formed. With bales formed in such manner, the need for some type of binding to hold the bale together in its generally cylindrical configuration after it has been discharged from the baler has been recognized from the outset. Accordingly, it has become conventional, as the final phase of formation of a bale in a rotary baler, to continue rotating the bale after it has attained essentially the desired size, while introducing to the periphery of the rotating bale the distal end stretch of a length of twine that is "picked up" by the rotating mass of hay, so that the length of twine may then be fed and guided relative to the rotating bale to form a binding around the bale in a pattern dependent upon the manner in which the twine is guided with respect to axial dimension of the rotating bale. The twine is typically fed from a container, reel or the like under appropriate tension through a guide tube whose twine dispensing extremity is shiftable along the axial dimension of the bale. U.S. Pat. No. 3,894,484 (Anstey et al.), U.S. Pat. No. 4,022,120 (McAllister), and copending application for U.S. Pat. Ser. No. 06/043,504 entitled "Interlacing Twine Wrapping Mechanism for Rotary Balers", filed Apr. 1, 1979, by Melvin V. Gaeddert which is owned by the same assignee as this invention, illustrate typical forms of rotary balers equipped with twine wrapping mechanisms.
A variety of techniques and mechanisms for controlling movement of the twine guiding tube have been tried, ranging from a simple rope tied to the guide tube to be manually pulled by a baler operator for shifting the discharge end of the guide tube along the axial dimension or "length" of the bale to surprisingly complex mechanical, electrical and even fluid powered arrangements. Those of such prior devices which have achieved any substantial acceptance as being practicable, however, have typically required the attention during wrapping of the bale of the baler operator and some continuing manual control by him over the movement of the twine guiding tube. For example, the above-mentioned U.S. Pat. No. 4,022,120 teaches movement of the guide tube by means of a reversible electric motor, which is energized to run in either direction or is deenergized by manipulation of a manual switch by the operator of the baler.
The conventional method of wrapping a bale and the result thereof may be most expeditiously explained with reference to FIG. 1, wherein a cylindrical bale wrapped in accordance with prevailing practice is illustrated in its completed form and is generally designated 10. The wrapping twine is generally designated 12 and includes a distal stretch 14 initially introduced to the bale 10 during rotation of the latter (the endmost portion of which it will be understood was "picked up" and became typically somewhat embedded in the rotating hay, so as to be obscured from view in the drawing), a relatively small number of convolutions 16 spiralled around the circumference of the bale 10 in a direction toward what is sometimes referred to as the "remote" end 18 of the bale 10, a sufficient number of convolutions 20 spiralled in the opposite direction along the length of the bale 10 to reach a point adjacent what is sometimes referred to as the "home" end 22 of the bale 10, and a terminal end stretch 24 typically hanging loosely from the bale 10 where the twine 12 was automatically cut off as the twine guide approached the end 22 of bale 10 by a mechanism normally provided for that purpose in balers provided with powered wrapping equipment. Assuming that the bale 10 will be rotating at a substantially constant rate during wrapping, the direction of spiralling of the convolutions 16, 20 will be determined by the direction in which the twine guide tube is then being moved relative to the length of the bale 10, and the spacing between adjacent convolutions 16 or 20 will be determined by the rate at which the guide tube is being so moved. It should also be noted that the twine dispensing extremity of the guide tube normally moves in an arc from a standby position directed toward the "home" end of the bale 10 but spaced outwardly from the bale 10, through a position of nearest proximity to the bale 10 while directed toward the mid-point of the latter, to a position directed toward the "remote" end of the bale 10 but spaced outwardly from the latter, and, of course, back to the mentioned standby position.
The detailed steps involved in forming the conventional pattern of binding convolutions 16, 20 shown in FIG. 1 in accordance with conventional techniques would typically include: formation of the bale 10 by the accumulation and rotation of hay while the baler is moving through the field, during which the twine guide will be in its standby position directed toward the "home" end 22 of the bale 10; action by the operator to stop the baler from further movement through the field for the purpose of wrapping the bale 10 already in the baler when it attains appropriate size, since there would be no place to put additional hay until the bale 10 has been wrapped and discharged from the baler; with the baler continuing to rotate the bale 10, action by the operator to initiate movement of the twine guide from its standby position toward the "remote" end 18 of the bale 10, in response to which the twine dispensing extremity of the twine guide swings inwardly toward the bale 10 as it is moved toward the "remote" end 18 of the bale 10 until, at a zone of the bale 10 usually somewhat beyond its mid-point, the distal stretch 14 of the twine 12 has moved into contact with and been "picked up" by the rotating hay mass of which the bale 10 is formed; the winding of the spiralled convolutions 16 upon the bale 10 as the disposition in which the twine guide is directed moves in the direction of the end 18 of the bale 10; action by the operator to reverse the direction of movement of the twine guide back toward the "home" end 22 of the bale 10, responsive to which the convolutions 20 are wound upon the bale 10; normally automatic cutting of the twine 12 at the end of the terminal stretch 24 thereof as the twine guide closely approaches its "home" position directed toward the end 22 of the bale 10; and action by the operator to stop the movement of the twine guide in its "home" or standby position. Attempts have been made to relieve the operator of the responsibility for reversing the movement of the twine guide when it reaches its fully actuated position directed toward the "remote" end 18 of the bale 10 or/and terminating movement of the twine guide when it subsequently returns to its standby position by some mechanical or electrical means such as limit switches, but such efforts have generally either resulted in undue complexity when a mechanical arrangement is employed or in objectionable impairment of reliability and increased maintenance requirements due to the adverse environment in which limit switches would have to be installed and operated.
As those skilled in the art are aware, the necessity for stopping the baler in the field during the wrapping of each bale 10 renders the wrapping operation a very critical one from the time and efficiency standpoint, and prior approaches to the problem have simply failed to provide a fully satisfactory solution involving a method utilizing automatic control to minimize both the attention and manual activity required of the operator and the period of time for completing the wrapping of each bale 10 once it has attained the proper size.
An even more serious deficiency with the conventional prior method of wrapping a bale 10, however, is the fact that the pattern of single strand bindings produced simply has proven inadequate to reasonably assure the structural integrity of bales 10 wrapped in that manner. Particularly during handling and transportation of bales 10 so wrapped, as well as even during initial discharge of the bale 10 from the baler, an intolerable number of such conventionally wrapped bales suffer breakage of one or more of the binding convolutions 16 and 20 due to the distortional forces that occur in such relatively massive bodies of hay during movement thereof or impact therewith. Thus, those skilled in the art have continued to search for a truly satisfactory method for wrapping bales of hay during rotation thereof in a rotary baler, but, insofar as we are aware, no such fully satisfactory method has heretofore been found nor suitable apparatus developed for implementing any such answer to the problem.